# [texhax] Formulas not rendering on site

Uwe Lueck uwe.lueck at web.de
Mon Oct 19 16:20:43 CEST 2015

Last Thursday, Jacob David Tafoya" wrote:
> I recently became the new IT Manager for one of the math departments
> at our university and inherited a MediaWiki site which uses TeX version
> 3.141592 (Web2C 7.5.6) on Red Hat 6.7. None of the formulas are rendering
> and instead show the HTML source, similar to this:
> $\frac{dT}{dt}=r_{2}T(1-bT)-\frac{aET}{g_{2}+T}$.
> I have no clue how long this issue has been going on. There have been no
> changes to this site apart from a faculty member adding to the MediaWiki
> page- no system changes have been done in many years.
>
> I researched the issue for about 2 hours and can’t really find a solid
> answer as to why the formulas aren’t rendering. My first thought was to
> update TeX using tlmgr update –all but this cannot be done since tlmgr is
> not installed and I do not have root access to install it.

This makes me curious about how MediaWiki actually invokes TeX. Googling...

https://www.mediawiki.org/wiki/Texvc

where I find:

"texvc in its turn requires three additional programs, ocaml, LaTeX and
under the special (not default!) names, specific for each server. In
particular, if one already has LaTeX installed under any other place,
then, by default, it will not be used and the wiki-format of the formulas
will not be supported."

One may guess from this that installing LaTeX to a wrong place may break the
formulas, and that this actually happened.

The text continues by saying that the rest of the above webpage teaches how to
install texvc et al. properly. You might /either/ check whether the site could
be the result of that procedure -- or how it differs, then tweak it -- /or/
uninstall LaTeX (et al.) and reinstall it (them) from scratch following those
instructions.

Hope a little that helps

-- Uwe.